lib/vsnprintf.c

   1 /*
   2  * vsnprintf()
   3  *
   4  * Poor substitute for a real vsnprintf() function for systems
   5  * that don't have them...
   6  */
   7
   8 #include "compiler.h"
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <stdarg.h>
  13 #include <string.h>
  14
  15 #include "nasmlib.h"
  16
  17 extern efunc nasm_malloc_error;
  18
  19 #define BUFFER_SIZE     65536   /* Bigger than any string we might print... */
  20
  21 static char snprintf_buffer[BUFFER_SIZE];
  22
  23 int vsnprintf(char *str, size_t size, const char *format, va_list ap)
  24 {
  25     int rv, bytes;
  26
  27     if (size > BUFFER_SIZE) {
  28         nasm_malloc_error(ERR_PANIC|ERR_NOFILE,
  29                           "snprintf: size (%d) > BUFFER_SIZE (%d)",
  30                           size, BUFFER_SIZE);
  31         size = BUFFER_SIZE;
  32     }
  33
  34     rv = vsprintf(snprintf_buffer, format, ap);
  35     if (rv >= BUFFER_SIZE) {
  36         nasm_malloc_error(ERR_PANIC|ERR_NOFILE,
  37                           "snprintf buffer overflow");
  38     }
  39
  40     if (size > 0) {
  41         if ((size_t)rv < size-1)
  42             bytes = rv;
  43         else
  44             bytes = size-1;
  45
  46         memcpy(str, snprintf_buffer, bytes);
  47         str[bytes] = '\0';
  48     }
  49
  50     return rv;
  51 }